escort seatbelts

Hi All,
Has anyone fitted rear retractable seat belts in a mark 2 escort? I know that they were an option in Ghia models but haven't founf an aftermarket version.  what route does the belt take inside the cab- does it go down behind the seat back and round to the mounting point in the front of the arch so its out of sight? Any pics or info would be helpful.
 
Cheers,
 
Len